The force behind physics demonstrations

In a large, empty Dennison lecture hall Friday afternoon, three people wheeled in a large copper Tesla coil, a device that produces high-voltage, low-current electricity. After efficiently setting everything up, the device was powered on. An off-kilter electric sound filled the hall and bright blue sparks emanated from the coil’s top in seemingly random directions. Two people slowly walked around the coil — intently checking for misplaced internal connections.

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The power was cut. Someone mentioned the machine sounded off, and a protective shielding panel on the device was removed. An internal part was adjusted — by mere millimeters — and the machine was powered on again. This process was repeated over and over: turn off, small adjustment, turn on, listen, look, try again until it was just right.

The employees at the University’s Physics Demonstration Lab had to make sure this demonstration — one of their more dangerous — was correctly calibrated because, well, that’s just what they do: Build, correct and perfect.

Buried in the basement of Dennison, accessible through a second story staircase or going through one of two lecture halls, a team of three works daily to imagine, build and perfect in-class physics demonstrations and experiments. From simply visualizing an electronic field to loudly showing the effects of a Tesla coil, the Physics Demonstration Lab is used to increase learning and occasionally awaken napping students in physics classes everyday.

Building to educate

A demonstration is first thought out and planned, then gets prototyped for feasibility. If the project is deemed successful, a first build is done and sometimes second and third remakes are required because of durability, weight or myriad other concerns. Eventually it is deemed classroom ready and added to the catalogue. Even at this stage, the demonstration can still be changed and updated as feedback is received.

Laboratory Manager Warren Smith and Lecture Demonstrators Monika Wood and Matthew Jackson arrive one hour before a class starts. They see the schedule of demonstrations for the day with many last minute additions from professors and set up what’s needed for the first block of classes on movable carts.

While classes are in session, the three set up experiments for the next class, while working to fix and refine demonstrations. The basement laboratory is a curious scientist’s paradise. Situated just yelling distance from the lecture halls — in case anything goes wrong — the large space consists of a small office with computers, a large shelved storage area and a workroom.

With the feel of the warehouse on Discovery’s “Mythbusters,” the lab has a large assortment of, well, almost anything. Children’s toys, saws, wires, speakers of every size, all carefully organized and put away. When a professor has an idea for a new experiment, Smith and his coworkers know what needs to be bought and what is already on hand.

As class time approaches, the lab busies with activity, and when class is finally dismissed, there is a NASCAR-esque pit crew race to move the experiments out of the classrooms and move new ones in. Chalkboards wiped down experiments set up, in under 10 minutes.

All professors need to do is actually run and explain the demonstrations during class.

Demonstrated learning

Typically used in large lecture halls — where introductory science classes are often held — the demonstrations break up monotonous classes but also reinforce learning in their own right.

In-class demonstrations can primarily benefit learning in two ways, according to Rachel Niemer, associate director for the University’s Center for Research on Learning and Teaching. Aside from providing a break during long lectures, the demonstrations make students actively think about the material instead of passively ingesting it.

University professors view the demonstrations as one tool to help make lessons stick in the minds of easily distracted students. Students view the experiments as a welcome reprieve from PowerPoint presentations and another way to help grasp a concept.

“Usually when you teach something, some new idea, new concept, you want the students to immediately come to grips with it,” Physics Prof. Gregory Tarlé said. “You want them to see that what you’re teaching them has applications in real life. You want to make that connection by showing them the demonstration.”

Professors are always calling, e-mailing and visiting the physics lab. Many times, they are just ordering an experiment for class from the large catalogue of experiments that have already been built and tested by the lab. Frequently, however, professors are calling with a new idea for an experiment, asking to see if a concept can be shown in demonstration form, or even just offering or asking for improvements for an already created one.

For members of the lab and the professors and lecturers who use it, this communication is key to the lab’s success.

Timothy McKay, the Arthur F. Thurnau professor of physics and astronomy, said having a dedicated team encourages professors to come up with innovative teaching methods for class, which wouldn’t be possible if the support weren’t there. Without the lab, professors wouldn’t even attempt to use some of the technology they do now.

McKay said using demonstrations in science classes — specifically in physics — has a long history, with books on the subject dating back to the early 20th century. Physicists say the field is all about explaining the real world and, especially in introductory classes, many of the phenomena can be shown to students directly.

Keeping it simple

Some demonstrations are essentially unchanged from the 1900s, only getting rebuilt when needed. Others are frequently remade and created.

For Smith, who has been with the lab for 18 years, an experiment can always be improved — rebuilt, repainted, rethought. However, he believes simplicity is key. It is about properly meeting the needs of both those who will use and see the demonstration.

Smith said demonstrations are superior to videos and simulations.

“There’s just no replacement for the real thing. It has an impact, a visceral impact, upon all of your senses and your body,” Smith said.

While a demonstration may appear simple in its final form, there is thought that goes into every facet of its design: the size and color of wiring, the speed of the reaction and even colors that contrast with blackboards.

“We just have a whole list of things that we look at when we construct an experiment that unless it meets all that criteria, it’s subject to rebuild at anytime,” Smith said.

He said the perfect experiment is one that clearly shows a single concept. Bored students should be interested in what happens, and it must be controllable by professors. A good demonstration is simple to understand and easy to see — from both nearby and in the top row.

McKay said the physics faculty embraces these demonstrations, particularly in introductory classes. He said when used properly the demonstrations can be one of the best ways to really drive home a point.

“Demonstrators are one of the ways that we can send our students out wanting to tell their roommate about what happened in class today,” McKay said. “When you do that, it’s not just a piece of theater, because that kind of memorable nature is learning. You stick something in a person’s brain in a way that stays by giving it that framing.”